DOCSLIB.ORG

(2014) – the History and Dynamics of a Welded Pyroclastic

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(2014) – the History and Dynamics of a Welded Pyroclastic Bull Volcanol (2014) 76:811 DOI 10.1007/s00445-014-0811-0 RESEARCH ARTICLE The history and dynamics of a welded pyroclastic dam and its failure Graham D. M. Andrews & James K. Russell & Martin L. Stewart Received: 17 July 2013 /Accepted: 15 February 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract The 2,360 BP eruption of Mount Meager, British approximately 8 h and eroded a 2.5-km long canyon into the Columbia began as an explosive, dacitic sub-Plinian eruption still-hot dam core before returning to background flow rates. that waned rapidly to a sustained period of Vulcanian, eruption-triggered dome collapse events producing volumi- Keywords Block and ash flows . Volcanic dams . Welding . nous block and ash flow (BAF) deposits. The earliest BAF Dam failure . Lahar deposits accumulated rapidly enough immediately downslope of the vent to retain heat and weld; using the deposit as a paleoviscometer determines an effective viscosity of 109– Introduction 1010 Pa s during welding. This prolific production of hot lava and block and ash flows, in a steep mountainous terrain, Pyroclastic density currents and volcanic mudflows (“lahars”) created a ∼110 m high, largely impermeable dam capped by account for 40 to 50 % of all fatalities related to volcanic permeable, non-welded BAF deposits and unconsolidated eruptions (Auker et al. 2013) including the greatest volcanic avalanche deposits that blocked the flow of the Lillooet disasters of the twentieth century (Mont Pelée, Martinique, River and created a temporary lake. The welded pyroclastic 1902; Nevada del Ruiz, Colombia, 1985). Although pyroclas- dam was compromised and overtopped at least once before tic density currents have the potential to cause tens of thou- the peak dam height was reached. Renewed eruption caused sands of fatalities as infrequent events, lahars cause tens to buildup of the dam to a maximum of 780 m above sea level hundreds of fatalities annually (Auker et al. 2013). Lahars are (asl) and grew the temporary lake to an elevation of 740 m asl particularly challenging hazards to plan for, and mitigate and a minimum volume of 0.55 km3. The rise of lake level led against, because they can occur during and for several years to catastrophic failure of the top of the dam, generating an after an eruption (Manville and Cronin 2007). Many lahars outburst flood that carved a canyon through most of the dam result from the post-eruption failure of temporary lava- and resulted in a voluminous lahar that is traced at least 65 km generated dams (e.g., Fenton et al. 2006) and volcaniclastic- downstream. Based on current flow rates of the Lillooet River, generated dams (Capra 2007), and the associated catastrophic the lake would have overtopped the final dam at a minimum of release of the impounded lake. Examples include the 1982 39–65 days after its formation. The peak deluge lasted eruption of El Chichón, Mexico (Macías et al. 2004); Nevado de Colima, Mexico (Capra and Macías 2002); Ruapehu 2007, New Zealand (Manville and Cronin 2007); and Numazawa, Editorial responsibility: V. Manville Japan (Kataoka et al. 2008). In this paper, we describe and interpret the proximal and * G. D. M. Andrews ( ) medial volcanic deposits associated with damming of the Department of Geosciences, California State University Bakersfield, Bakersfield, CA 93311, USA Lillooet River during the 2,360 BP eruption of Mount e-mail: [email protected] Meager, B.C. We use field observations to reconstruct the : : temporal and spatial building of the dam, including the height G. D. M. Andrews J. K. Russell M. L. Stewart and duration of the dam, the size of the lake, and the down- Volcanology & Petrology Laboratory, Department of Earth & Ocean Sciences, University of British Columbia, Vancouver, BCV6T 1Z4, stream extent of the outburst debris flow deposits. Our work Canada provides semiquantitative estimates on the rates, volumes, and 811, Page 2 of 16 Bull Volcanol (2014) 76:811 timescales of dam-building, lake-filling, and dam failure. This Fig. 2 a Map of the 2,360 BP Pebble Creek Formation (modified from is the first described occurrence of a partially welded pyro- Hickson et al. 1999). b Non-exaggerated oblique south-southwest view of clastic dam and a rare case where field evidence can elucidate the Mount Meager volcanic complex (MMVC) and Lillooet River valley (adapted from Google EarthTM). c Panorama and dimensions of the the timescales of events preceding and attending the failure of canyon incised into unit A; viewed downstream (east-southeast) from a volcanic dam (cf. Capra 2007). Keyhole Falls Geological setting The southern Coast Mountains of British Columbia (Fig. 1) have been characterized by rapid uplift rates and enhanced Mount Meager volcanic complex glaciofluvial erosion rates over the past 4 Ma (Clague et al. 1982;Andrewsetal.2012). The MMVC is now highly The 2,360 BP eruption of the Mount Meager volcanic com- dissected and its base is perched at 1,100–1,200 m above plex (MMVC), Cascades arc, British Columbia (Fig. 1; Read sea level (asl), more than 500 m above the present-day erosion 1977) is the youngest explosive volcanic event in Canada surface marked by the base of the adjacent Lillooet River (Hickson et al. 1999). The eruptive center poses a significant valley (400–600 m asl; Fig. 2). The 2,360 BP eruption vent risk to local communities from both volcanic eruptions and is situated immediately above the narrow and steep-sided, non-volcanic mass-wasting events (Simpson et al. 2006; glaciated valley hosting the Lillooet River, and, as a conse- Friele et al. 2008). quence, this portion of the Lillooet River valley is partially filled with a thick (0–180 m) accumulation of proximal pyro- clastic deposits. MT. MEAGER Physiography of Upper Lillooet River valley The Upper Lillooet River valley (Fig. 2a) is a steep-sided, narrow, glaciated valley situated immediately north of the British ∼ Columbia MMVC and extending 16 km upstream towards the Lillooet icefield (Fig. 2b). The Lillooet drainage was sculpted by Late EXPLORER inset Pleistocene glaciation; however, the post-glacial physiography PLATE of the Lillooet River is significantly different along a ∼2.5 km stretch immediately below the MMVC and southeast of Keyhole Falls (Fig. 2a), where it has been infilled by deposits Washington of the Pebble Creek Formation (PCF: Hickson et al. 1999). At Keyhole Falls, two morphologically distinct canyons JUAN DE FUCA are carved into PCF deposits—(1) a <150 m deep, ∼300 m PLATE wide, horseshoe-shaped canyon (Fig. 2c) carved through the entire thickness of the PCF to the basement and (2) a 60 m deep, <15 m wide slot canyon carved into welded BAF MOUNT MEAGER Oregon VOLCANIC deposits (Fig. 3a). The larger horseshoe-shaped canyon is COMPLEX straight, rough sided, rubble strewn, and extends approximate- Lillooet ly 2.5 km downstream of Keyhole Falls. The smaller slot River canyon is short (<1 km in length), sinuous, and has water- Pemberton polished vertical surfaces and extends upstream of Keyhole Falls. Mt. Cayley The slot canyon is typical of perennial water-carved slot Whistler canyons (e.g., Carter and Anderson 2006) resulting from California steady long-term stream flow and abrasion. However, the scale, shape, and textural morphology of the larger canyon Mt. Garibaldi (Fig. 2c) are atypical of fluvially carved canyons. The width Squamish and depth of the canyon are at least an order of magnitude 0 20 km 0 200 km larger than can be supported by the present-day fluvial dis- charge. Such misfit stream–canyon relationships commonly Fig. 1 Map of the Cascade volcanic arc (triangles) of western North America, in southern British Columbia, Canada, and location of Mount indicate rapid and sudden alteration of local drainage systems Meager (inset) within the Garibaldi volcanic belt (e.g., local tectonism, enhanced glacial erosion, or outburst Bull Volcanol (2014) 76:811 Page 3 of 16, 811 a 2200 2000 1800 1600 Salal Creek 800 Lillooet 1200 1400 River 1000 N 800 Keyhole Falls 1000 1200 1400 1600 PCF inferred vent 1000 2000 800 2200 Plinth Peak 2400 600 Meager Creek 400 b Lillooet Icefield MMVC inferred vent Lillooet River Meager Creek Lillooet River Keyhole Falls Salal Creek N c non-welded block & ash flow and sedimentary deposits 90 m welded block & ash flow deposit ~300 m 811, Page 4 of 16 Bull Volcanol (2014) 76:811 a simplified lithostratigraphy at Keyhole Falls 780 non-welded block and ash flow deposits unit C BAF, gravel, and rock avalanche 700 slot-canyon deposits unit B resistant 3C surface welded block 3B and ash flow deposits unit A 600 m asl b c unit C welded BAF deposit non-welded BAF unit B & rock avalanche deposits welded BAF deposit sand and gravel unit A Fig. 3 a The pyroclastic dam at Keyhole Falls (looking northwest) and volcaniclastic succession (unit B) buried by a later non-welded BAF the Keyhole Falls slot canyon. The locations of photos b and c are shown. deposit (unit C); note the presence of alternating recessive (soft, non- b Close-up of irregularly fanning columnar joints in unit A in the canyon welded BAF, sand, gravel, and rock avalanche deposits) and cliff-forming wall at Keyhole Falls (courtesy of Paul Adams); the slot canyon is 60 m (hard, welded BAF deposits) horizons deep. c View of the northern canyon wall and the 45-m thick clastic and floods). Other examples in volcanic settings include down- et al. 1996; Hickson et al. 1999). The intensity of the eruption stream of Lake Taupo (Manville et al. 1999;Manvilleand waned to a Vulcanian explosive phase (Michol et al. 2008) Wilson 2004) and Lake Tarawera in New Zealand (Hodgson producing a sequence of welded (early) and non-welded (late) and Nairn 2005;Manvilleetal.2007).
Load more

Recommended publications
  • Dacite Block and Ash Avalanche Hazards in Mountainous Terrain: 2360 Yr
    DACITE BLOCK AND ASH AVALANCHE HAZARDS IN MOUNTAINOUS TERRAIN: 2360 YR. BP ERUPTION OF MOUNT MEAGER, BRITISH COLUMBIA by MARTIN L. STEWART B.Sc, (Honours), Carleton University, 1998 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF EARTH AND OCEAN SCIENCES We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA December 2002 © Martin L. Stewart, 2002 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of LoM^ r QatA^ Sc/t^n? The University of British Columbia Vancouver, Canada Date IB * zooi DE-6 (2/88) Abstract The Mount Meager volcanic complex hosts deposits from the youngest known explosive volcanic eruption in Canada (2360 yr. BP). These deposits reflect the consequences of erupting dacite magmas into a region of extreme topographic relief. Regions of this kind represent one of the most hazardous and, potentially, high risk natural environments on the planet. Mapping of the Pebble Creek Formation deposits has elucidated a unique distribution of hazardous events of varying intensity, timing, and frequency associated with the 2360 yr.
    [Show full text]
  • Dynamics of Aboriginal Land Use Institutions: the Rise and Fall of Community Control Over Reserve Systems in the Lil'wat Nation, Canada
    DYNAMICS OF ABORIGINAL LAND USE INSTITUTIONS: THE RISE AND FALL OF COMMUNITY CONTROL OVER RESERVE SYSTEMS IN THE LIL'WAT NATION, CANADA Akihiko Nemoto Forest Economics Research Institute #301 Mansion Yoneda, 2-13-12 Hakusan, Bunkyo-Ku, Tokyo, Japan zip 112-0001 E-mail: [email protected] Abstract I Resume Through a combination of the participant-observer method and archival data collection, this descriptive study deals with the changing dynam­ ics of land use institutions in an Aboriginal community of British Columbia, Canada, namely the LiI'wat Nation. En alliant la methode du participant-observateur et la collecte de donnees d'archives, I'etude descriptive se penche sur la dynamique en evolution des institutions responsables de I'utilisation du sol dans une collectivite autochtone de la Colombie-Britannique (Canada), soit la Nation Lil'wat. The Canadian Journal of Native Studies XXII, 2(2002}:207-237. 208 Akihiko Nemoto 1. Research Objectives and Methodology In the context of "sustainable development," traditional resource use systems around the world have been gaining attention as practical ways to conserve natural resources today.1 With respect to Aboriginal peoples in Canada, some scholars have advocated that there is a strong hope for contemporary resource management practices to incorporate the Aboriginal knowledge that has sustained the living resource base over extended periods of time.2 However, these arguments tend to fol­ low only philosophical lines, ignoring the reality of Aboriginal people who have been subjected to the politics of assimilation and economic modernization. As a way to explore Aboriginal relationship to land against the reality of their life, it is worthwhile investigating de facto land use institutions evolving in an Aboriginal community.
    [Show full text]
  • Volcanic Landslide Risk Management, Lillooet River Valley, BC: Start of North and South Fsrs to Meager Confluence, Meager Creek and Upper Lillooet River
    Volcanic Landslide Risk Management, Lillooet River Valley, BC: Start of north and south FSRs to Meager Confluence, Meager Creek and Upper Lillooet River. Submitted to: Malcolm Schulz, RPF Engineering Officer Metro Vancouver Squamish District Ministry of Forests, Lands and Natural Resource Operations Submitted by: Pierre Friele, P. Geo. Cordilleran Geoscience, PO Box 612, 1021 Raven Drive, Squamish, BC V8B 0A5 March 10, 2012 Table of Contents Introduction ......................................................................................................................... 1 Scope ................................................................................................................................... 1 Hazard & Risk Assessment ................................................................................................. 1 Volcanic Landslide Hazard ................................................................................................. 2 Hazard Frequency and Magnitude .................................................................................. 2 Affected Areas ................................................................................................................ 3 Proximal Zones ........................................................................................................... 3 Distal Zone .................................................................................................................. 4 Consequences of Volcanic Landslide Impacts ..............................................................
    [Show full text]
  • Discrimination of Hot Versus Cold Avalanche Deposits: Implications for Hazards Assessment at Mount Meager, British Columbia
    Geological Survey of Canada CURRENT RESEARCH 2001-A10 Discrimination of hot versus cold avalanche deposits: implications for hazards assessment at Mount Meager, British Columbia M.L. Stewart, J.K. Russell, and C.J. Hickson 2001 ©Her Majesty the Queen in Right of Canada, 2001 Catalogue No. M44-2001/A10E ISBN 0-660-18390-0 A copy of this publication is also available for reference by depository libraries across Canada through access to the Depository Services Program's website at http://dsp-psd.pwgsc.gc.ca A free digital download of this publication is available from the Geological Survey of Canada Bookstore web site: http://gsc.nrcan.gc.ca/bookstore/ Click on Free Download. All requests for permission to reproduce this work, in whole or in part, for purposes of commercial use, resale or redistribution shall be addressed to: Earth Sciences Sector Information Division, Room 200, 601 Booth Street, Ottawa, Ontario K1A 0E8. Authors’ addresses M.L. Stewart ([email protected]) J.K. Russell ([email protected]) Igneous Petrology Laboratory Earth and Ocean Sciences The University of British Columbia 6339 Stores Road Vancouver, B.C. V6T 1Z4 C.J. Hickson ([email protected]) GSC Pacific, Vancouver 101-605 Robson Street, Vancouver, B.C. V6B 5J3 Discrimination of hot versus cold avalanche deposits: implications for hazards assessment at Mount Meager, British Columbia M.L. Stewart, J.K. Russell, and C.J. Hickson GSC Pacific, Vancouver Stewart, M.L., Russell, J.K., and Hickson, C.J., 2001: Discrimination of hot versus cold avalanche deposits: implications for hazards assessment at Mount Meager, British Columbia; Geological Survey of Canada, Current Research 2001-A10, 10 p.
    [Show full text]
  • Implications for Hazard Assessment at Mount Meager, BC
    Discrimination of hot versus cold avalanche deposits: Implications for hazard assessment at Mount Meager, B.C. M. L. Stewart, J. K. Russell, C. J. Hickson To cite this version: M. L. Stewart, J. K. Russell, C. J. Hickson. Discrimination of hot versus cold avalanche deposits: Implications for hazard assessment at Mount Meager, B.C.. Natural Hazards and Earth System Sciences, Copernicus Publ. / European Geosciences Union, 2003, 3 (6), pp.713-724. hal-00299093 HAL Id: hal-00299093 https://hal.archives-ouvertes.fr/hal-00299093 Submitted on 1 Jan 2003 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Natural Hazards and Earth System Sciences (2003) 3: 713–724 © European Geosciences Union 2003 Natural Hazards and Earth System Sciences Discrimination of hot versus cold avalanche deposits: Implications for hazard assessment at Mount Meager, B.C. M. L. Stewart1, J. K. Russell1, and C. J. Hickson2 1Igneous Petrology Laboratory, Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia, Canada 2Pacific Division, Geological Survey of Canada, Vancouver B.C., Canada Received: 5 February 2003 – Revised: 26 May 2003 – Accepted: 29 May 2003 Abstract. The surficial deposits surrounding the Mount represent an obvious hazard and, in many instances, the na- Meager volcanic complex include numerous avalanche de- ture or magnitude of these volcanic hazards can be substan- posits.
    [Show full text]
  • Could Glacial Retreat-Related Landslides Trigger Volcanic Eruptions? Insights from Mount Meager, British Columbia
    Could Glacial Retreat-Related Landslides Trigger Volcanic Eruptions? Insights from Mount Meager, British Columbia Gioachino Roberti, Brent Ward, Benjamin van Wyk de Vries, Nicolas Le Corvec, Swetha Venugopal, Glyn Williams-Jones, John J. Clague, Pierre Friele, Giacomo Falorni, Geidy Baldeon, Luigi Perotti, Marco Giardino, and Brian Menounos Abstract chamber at 3–16 km depth. Based on numerical model simulations carried out to constrain the stress change, the Mount Meager, a glacier-clad volcanic complex in British failure would affect the stress field to depths of up to Columbia, Canada, is known for its large landslides, as *6 km, with changes in effective stress of up to well as a major eruption about 2360 years ago. In 2010, *4 MPa. The change in effective stress following such after decades of glacier retreat, the south flank of Mount a landslide might destabilize the magmatic chamber and Meager collapsed, generating a huge (53 Mm3) landslide. trigger an eruption. This result also suggests that a In 2016, fumaroles formed ice caves in one of the glaciers previously documented major flank collapse may have on the complex. This glacier is bordered by a large had a role in the 2360 cal yr BP eruption. unstable slope presently moving about 3.5 cm per month. If this slope were to fail, a long-runout debris avalanche Keywords would reach the floor of the Lillooet River valley, with possible destructive effects on downstream infrastructure. Volcanic landslide Á Stress changes Á Eruption trigger Á The unloading of the volcanic edifice from an abrupt FEM Á InSAR failure would also have unknown effects on the magmatic plumbing system.
    [Show full text]
  • Impact of a Quaternary Volcano on Holocene Sedimentation in Lillooet River Valley, British Columbia
    Sedimentary Geology 176 (2005) 305–322 www.elsevier.com/locate/sedgeo Impact of a Quaternary volcano on Holocene sedimentation in Lillooet River valley, British Columbia P.A. Frielea,T, J.J. Clagueb, K. Simpsonc, M. Stasiukc aCordilleran Geoscience, 1021, Raven Drive, P.O. Box 612, Squamish, BC, Canada V0N 3G0 bDepartment of Earth Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6; Emeritus Scientist, Geological Survey of Canada, 101-605 Robson Street, Vancouver, BC, Canada V6B 5J3 cGeological Survey of Canada, 101-605 Robson Street, Vancouver, BC, Canada V6B 5J3 Received 3 May 2004; received in revised form 15 December 2004; accepted 19 January 2005 Abstract Lillooet River drains 3850 km2 of the rugged Coast Mountains in southwestern British Columbia, including the slopes of a dormant Quaternary volcano at Mount Meager. A drilling program was conducted 32–65 km downstream from the volcano to search for evidence of anomalous sedimentation caused by volcanism or large landslides at Mount Meager. Drilling revealed an alluvial sequence consisting of river channel, bar, and overbank sediments interlayered with volcaniclastic units deposited by debris flows and hyperconcentrated flows. The sediments constitute the upper part of a prograded delta that filled a late Pleistocene lake. Calibrated radiocarbon ages obtained from drill core at 13 sites show that the average long-term floodplain aggradation rate is 4.4 mm aÀ1 and the average delta progradation rate is 6.0 m aÀ1. Aggradation and progradation rates, however, varied markedly over time. Large volumes of sediment were deposited in the valley following edifice collapse events and the eruption of Mount Meager volcano about 2360 years ago, causing pulses in delta progradation, with estimated rates to 150 m aÀ1 over 50-yr intervals.
    [Show full text]
  • Guidance Towards a Landslide Risk Management Plan
    The Meager and Pebble Creek Hotsprings near Pemberton, British Columbia: Guidance towards a Landslide Risk Management Plan By Cordilleran Geoscience Box 612, Squamish, BC VON 3GO For Teressa McMillan Recreation Technician Ministry of Forests, Lands and Natural Resource Operations Sea to Sky District and South Sunshine Coast District Phone: 604-898-2132 Cell: 604-848-5006 March 17, 2017 Draft V1, March 17, 2017 Table of Contents 1.0 Introduction ............................................................................................................................... 1 2.0 Study Area ................................................................................................................................ 2 3.0 Landslide Hazard, Frequency, Magnitude and Consequence ................................................... 4 4.0 Hazards Affecting Mount Meager Volcanic Complex ............................................................. 5 4.1 Non-eruption Related Landslide Hazard Overview .............................................................. 5 4.2 Incidents Involving Risk to Human Life .............................................................................. 6 4.3 Hazards Affecting the Meager Creek Hotsprings Recreation Site ....................................... 7 4.3.1 Hydrologic Clear Water Floods ..................................................................................... 7 4.3.2 Coarse Woody Debris and Sediment Loading ............................................................... 8 4.3.3 Outburst floods..............................................................................................................
    [Show full text]
  • Land Use Planning Agreement Between the Lil'wat Nation and The
    LAND USE PLANNING AGREEMENT Between The LIL’WAT NATION And The PROVINCE of BRITISH COLUMBIA as represented by the Minister of Agriculture and Lands LAND USE PLANNING AGREEMENT Between: The LIL’WAT NATION And: The PROVINCE of BRITISH COLUMBIA (the Province) as represented by the Minister of Agriculture and Lands (each a Party and collectively the Parties) WHEREAS: A. The Province convened public forums for the Sea-to-Sky and Lillooet Land and Resource Management Plans, received recommendations from those forums and prepared documents entitled “Sea-to-Sky Land and Resource Management Plan Consultation Draft April 14, 2006" (Draft S2S LRMP) and the "Draft Lillooet Land and Resource Management Plan, July 22, 2004" (Draft Lillooet LRMP). B. The Territory of the Lil’wat Nation overlaps with the Sea-to-Sky and Lillooet LRMP areas. C. The Lil’wat Nation has prepared the Lil’wat Land Use Plan (LLUP) which represents the Lil’wat Nation vision for managing the Lil’wat Territory. D. The Parties signed a Statement of Principles which establishes a process to engage in Government-to-Government land use discussions with a goal of harmonizing the LLUP and the Sea-to-Sky LRMP. E. The Parties wish to establish this Agreement as an outcome of Government-to-Government discussions. F. The Province has committed to consult with the Lil’wat Nation on the development of a protocol that will set out how the Integrated Land Management Bureau and the Lil’wat Nation will work on matters of mutual interest. Lil’wat Nation – British Columbia Land Use Planning Agreement 1 FINAL G.
    [Show full text]
  • Factors Limiting Juvenile Sockeye Production and Enhancement Potential for Selected B.C
    Fisheries and Oceans Pêches et Océans Science Sciences C S A S S C C S Canadian Science Advisory Secretariat Secrétariat canadien de consultation scientifique Research Document 2001/098 Document de recherche 2001/098 Not to be cited without Ne pas citer sans permission of the authors 1 autorisation des auteurs 1 FACTORS LIMITING JUVENILE SOCKEYE PRODUCTION AND ENHANCEMENT POTENTIAL FOR SELECTED B.C. NURSERY LAKES K.S. Shortreed, K.F. Morton, K. Malange, and J.M.B. Hume Fisheries and Oceans Canada Marine Environment and Habitat Science Division 4222 Columbia Valley Highway Cultus Lake Laboratory, Cultus Lake, B.C. V2R 5B6 1 This series documents the scientific basis for 1 La présente série documente les bases the evaluation of fisheries resources in scientifiques des évaluations des ressources Canada. As such, it addresses the issues of halieutiques du Canada. Elle traite des the day in the time frames required and the problèmes courants selon les échéanciers documents it contains are not intended as dictés. Les documents qu’elle contient ne definitive statements on the subjects doivent pas être considérés comme des addressed but rather as progress reports on énoncés définitifs sur les sujets traités, mais ongoing investigations. plutôt comme des rapports d’étape sur les études en cours. Research documents are produced in the Les documents de recherche sont publiés dans official language in which they are provided to la langue officielle utilisée dans le manuscrit the Secretariat. envoyé au Secrétariat. This document is available on the Internet at: Ce document est disponible sur l’Internet à: http://www.dfo-mpo.gc.ca/csas/ ISSN 1480-4883 Ottawa, 2001 ABSTRACT In this report we present summaries of our current knowledge of freshwater factors limiting sockeye production from 60 B.C.
    [Show full text]
  • 0X0a I Don't Know Gregor Weichbrodt FROHMANN
    0x0a I Don’t Know Gregor Weichbrodt FROHMANN I Don’t Know Gregor Weichbrodt 0x0a Contents I Don’t Know .................................................................4 About This Book .......................................................353 Imprint ........................................................................354 I Don’t Know I’m not well-versed in Literature. Sensibility – what is that? What in God’s name is An Afterword? I haven’t the faintest idea. And concerning Book design, I am fully ignorant. What is ‘A Slipcase’ supposed to mean again, and what the heck is Boriswood? The Canons of page construction – I don’t know what that is. I haven’t got a clue. How am I supposed to make sense of Traditional Chinese bookbinding, and what the hell is an Initial? Containers are a mystery to me. And what about A Post box, and what on earth is The Hollow Nickel Case? An Ammunition box – dunno. Couldn’t tell you. I’m not well-versed in Postal systems. And I don’t know what Bulk mail is or what is supposed to be special about A Catcher pouch. I don’t know what people mean by ‘Bags’. What’s the deal with The Arhuaca mochila, and what is the mystery about A Bin bag? Am I supposed to be familiar with A Carpet bag? How should I know? Cradleboard? Come again? Never heard of it. I have no idea. A Changing bag – never heard of it. I’ve never heard of Carriages. A Dogcart – what does that mean? A Ralli car? Doesn’t ring a bell. I have absolutely no idea. And what the hell is Tandem, and what is the deal with the Mail coach? 4 I don’t know the first thing about Postal system of the United Kingdom.
    [Show full text]
  • Lil'wat Nation Fact Book [PDF]
    ´ ´ ´ ´ the Lil’wat Nation A Fact Book 2260 BC | Sites in our traditional territory 400–200 BC | Lil’wat people are well established We are the Lil’wat Nation, confirmed by carbon dating. in their traditional territory. an Interior Salish people We live in a stunning and dramatic landscape with Our geography — between two formidable mountain a rich biodiversity — a mysterious place of towering ranges — ensured our important role in the early regional mountains, ice fields, alpine meadows, white-water rivers, economy. We were traders. For centuries we bartered and braided river valleys that run to a milky colour due and exchanged all manner of goods with many other to the silt and clay deposited by glacial melt. First Nations, and later with non-aboriginal fur traders, miners and settlers. While the Lil’wat is a separate and distinct nation, it remains part of the St’át’imc group. Skilled fishers and hunters, we are closely tied to our land. The plant and animal resources of the high mountain Our language is called Ucwalmícwts. It is taught at both slopes and river valleys remain critically important to us. Xit’olacw Community School and Pemberton High School, Like our ancestors we have a profound and harmonious and through Simon Fraser University in cooperation with relationship with this land. the Mount Currie Ts’zil Learning Centre. First European contact came in 1793 when Alexander Most Lil’wat people live at Mount Currie, near the Mackenzie made his overland journey to the Pacific. confluence of the Lillooet and Birkenhead rivers, just Over the next two centuries traders, miners and settlers east of Pemberton, a two-and-a half hour drive north arrived in our territory, without an invitation.
    [Show full text]